Add MCP servers and custom tools for bots

Two new settings pages, MCPs and Tools. Super admins define them; super
admins and admins attach them to bots, to workspaces (every bot there),
or to every bot. Bots get them in chat replies and tasks.

- Custom tools: a JSON-schema of arguments plus an HTTP request, a script
  on the bot's computer, or a prompt, templated with {{args.x}} and
  {{env.KEY}}, secrets redacted from results.
- MCP servers: remote (URL and headers) or stdio commands run on the host
  with a setup command and an isolated env, in a per-process pool. Tools
  are listed into a cache and connect on first call.
- Add, edit, access and try open in modals.
- Markdown, JSON and command fields use twui's AceEditor (CodeEditor),
  its scripts loaded on demand.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/utils/load-ace-scripts.ts

@@ -0,0 +1,37 @@
+const AceScripts = [
+    "https://cdnjs.cloudflare.com/ajax/libs/ace/1.22.0/ace.min.js",
+    "https://cdnjs.cloudflare.com/ajax/libs/ace/1.22.0/ext-language_tools.min.js",
+];
+
+let loading: Promise<void> | undefined;
+
+/**
+ * Loads the ACE editor's scripts once per page, in order (the language
+ * tools need ACE itself), so only pages with an editor download them.
+ * twui's `AceEditor` waits for `window.ace` on its own.
+ */
+export default function loadAceScripts() {
+    if (typeof window == "undefined") return Promise.resolve();
+
+    loading ||= AceScripts.reduce(
+        (previous, src) =>
+            previous.then(
+                () =>
+                    new Promise<void>((resolve, reject) => {
+                        if (document.querySelector(`script[src="${src}"]`)) return resolve();
+
+                        const script = document.createElement("script");
+                        script.src = src;
+                        script.onload = () => resolve();
+                        script.onerror = () => reject(new Error(`Couldn't load ${src}`));
+                        document.head.appendChild(script);
+                    }),
+            ),
+        Promise.resolve(),
+    ).catch((error) => {
+        loading = undefined;
+        throw error;
+    });
+
+    return loading;
+}